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Synonyms

groundless

American  
[ground-lis] / ˈgraʊnd lɪs /

adjective

  1. without rational basis.

    groundless fears.
    Synonyms:
    idle, unjustified, unfounded, baseless
groundless British  
/ ˈɡraʊndlɪs /

adjective

  1. without reason or justification

    his suspicions were groundless
"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

  • groundlessly adverb
  • groundlessness noun

Etymology

Origin of groundless

before 900; Middle English: bottomless, unfathomable; Old English grundlēas. See ground 1, -less

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

A Kremlin spokesman rejected the allegations as groundless.

From The Wall Street Journal • Dec. 12, 2025

China accused Britain's Keir Starmer of making "groundless accusations" on Tuesday, a day after the prime minister said he would engage with Beijing but warned China posed a national security threat.

From Barron's • Dec. 2, 2025

In response, the corporation said Sir Ed's "continuing attacks on BBC journalism are completely groundless".

From BBC • Sep. 23, 2025

Lot of reasons for that, it’s not groundless optimism.

From Salon • Aug. 5, 2025

As it turns out, the theory is groundless; on the next Saturday, Pete even brings me a homemade Egg McMuffin as a treat.

From "Nickel and Dimed: On (Not) Getting By in America" by Barbara Ehrenreich

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.